Methods and systems for augmented reality

ABSTRACT

The present invention generally provides systems, methods and ophthalmic lenses for image display of a virtual image, such as the display of a holographic image. 
     According to the invention, an ophthalmic lens is advantageously configured for optimizing the visualization of said displayed virtual images.

FIELD OF THE INVENTION

The invention relates to methods and systems for augmented reality.

The invention relates more particularly to the visualisation of virtualimages.

BACKGROUND OF THE INVENTION

Head-mounted devices with display features are known in the art. Suchdevices include so-called ‘smart glasses’, which allow the wearerthereof to visualize images or text for augmented reality.

In order to improve wearer visual comfort, it is desirable to providemethods and systems wherein images and text are displayed in acustomized way that is specifically adapted to the wearer and/or to theworn device.

For ametropic wearers, visual comfort requires that suitable correctionis provided not only for ‘natural vision’ (vision of the environmentsurrounding the wearer), but also for the visualization of the virtualimage or holographic image.

For emmetropic wearers, correction for virtual vision may be required,for example following reduced reserve of accommodation, or for providingspecific vision in different gaze directions (for example near-visionversus far-vision).

SUMMARY OF THE INVENTION

The present invention generally provides systems, methods and ophthalmiclenses for image display of a virtual image.

According to the invention, an ophthalmic lens is advantageouslyconfigured for correcting the wearer's virtual vision. The vision may becorrected as follows: for an ametropic wearer, both natural vision andvirtual vision may be corrected. For an emmetropic wearer, theprescription data are deemed to be null, so that natural vision may notbe corrected, while virtual vision may be corrected, for example due tolack of reserve of accommodation. In such case, it is possible toprovide a correction for virtual vision as a function of gaze directionsand/or as a function of distance of visualization. In broad terms, theinvention relies on the implementation of a holographic mirror in anophthalmic lens. The mirror is a holographic mirror, in that it wasrecorded using a holography process. But according to the invention, theholographic mirror is for visualization purposes. This mirror is used toreflect a light beam generated form an image source, so as to cause thevisualization of the image by the wearer. The holographic mirror is notused to reconstruct a recorded holographic image (as is the case intraditional hologram viewing). Due to the recording, advantageouslyaccording to the invention, the mirror is imparted an optical function,that is able, to modify the wavefront of the light beam stemming fromthe image source, upon reflection onto said mirror. This allows tocorrect the virtual vision of the wearer, because the lens of theinvention (incorporating the mirror), can modify the light beam thatgenerates the image in the eye of the wearer.

The virtual image is thus not necessarily a holographic image. It can beany virtual image, such as a 2D or 3D image. The nature of the imageresults from the nature of the image source, not from the holographicnature of the holographic mirror. It is possible to use, as an imagesource, a holographic image source, in which case the virtual image is aholographic image.

Systems of the Invention

The present invention provides an ophthalmic lens supply system. Theophthalmic lens supply system is for providing an ophthalmic lensintended to be fitted onto a frame and worn by a wearer, wherein saidophthalmic lens comprises a holographic mirror and wherein said framecomprises a build-in image source configured for illuminating saidholographic mirror so as to cause, upon reflection onto said holographicmirror, the visualization of a virtual image by the wearer, wherein saidophthalmic lens is configured for correcting the wearer's virtualvision, said supply system comprising:

-   -   first processing means (PM1) configured for placing an order of        an ophthalmic lens, wherein said first processing means (PM1)        are located at a lens ordering side (LOS) and comprise:        -   inputting means (IM1) configured for the input of wearer            prescription data (WPD),        -   optionally, inputting means (IM2) configured for the input            of frame data (FD), wherein said frame data (FD) comprise at            least one image source data;    -   second processing means (PM2) configured for providing lens data        (LD) based upon wearer prescription data (WPD), wherein said        second processing means (PM2) are located at a lens        determination side (LDS) and comprise outputting means (OM)        configured for outputting said lens data (LD), and    -   first transmission means (TM1) configured for transmitting said        wearer prescription data (WPD) and optionally for transmitting        said frame data (FD), from said first processing means (PM1) to        said second processing means (PM2),        wherein said supply system optionally further comprises    -   manufacturing means (MM) configured for manufacturing an        ophthalmic lens based upon lens data (LD) and frame data (FD),        wherein said manufacturing means are located at a lens        manufacturing side (LMS), and    -   second transmission means (TM2) configured for transmitting said        lens data (LD) from said second processing means (PM2) to said        manufacturing means (MM),        wherein said manufacturing means (MM) comprise means configured        for recording a holographic mirror.

Methods of the Invention

The present invention provides a method for providing an ophthalmic lensintended to be fitted onto a frame and worn by a wearer, wherein saidophthalmic lens comprises a holographic mirror (HM) and wherein saidframe comprises a build-in image source configured for illuminating saidholographic mirror so as to cause, upon reflection onto said holographicmirror, the visualization of a virtual image by the wearer, wherein saidophthalmic lens is configured for correcting the wearer's virtualvision, said method comprising the steps of:

-   (a) providing an ophthalmic lens having a front surface and a rear    surface,    -   wherein said ophthalmic lens comprises a film (F) of unrecorded        holographic medium,    -   wherein said ophthalmic lens optionally further comprises an        amplitude modulation cell, for example selected from        electrochromic cells, polarizing cells and photochromic cells,-   (b) performing holographic recording of said holographic medium by    generating interference between a reference beam (RB) and an    illumination beam (IB) so as to provide an ophthalmic lens    comprising a holographic mirror (HM), wherein the holographic    recording is performed in an optical arrangement that takes into    account at least the configuration of the frame, and-   (c) optionally cutting the lens obtained from step (b).

In some embodiments, the optical recording of step (b) further takesinto account:

-   -   the distance of visualization (D) of said displayed virtual        image by the wearer when wearing the frame and/or    -   the direction of visualization of said displayed virtual image        by the wearer when wearing the frame and/or    -   the number of areas of the holographic mirror for the        visualization of said displayed virtual image by the wearer when        wearing the frame.

In some embodiments, the wearer is ametropic, the ophthalmic lens ofstep (a) is configured for correcting the wearer's ametropia for naturalvision and is selected from single-vision lenses, multifocal lenses, forexample selected from bifocal lenses, and progressive addition lenses.

In some embodiments, in the ophthalmic lens of step (a):

-   -   the unrecorded holographic medium is selected from dichromated        gelatins and photopolymers, and    -   the film (F) of unrecorded holographic medium is provided on the        front surface of the ophthalmic lens, on the rear surface of the        ophthalmic lens, or between the front surface and the rear        surface of the ophthalmic lens.

In some embodiments, the optical arrangement of step (b) is such thatthe illumination beam (IB) is spatially configured with:

-   -   one or more recording lenses (RL, RL1, RL2) selected from        unifocal lenses, multifocal lenses such as bifocal lenses, and        progressive addition lenses, or a lens matrix (LM), or an active        lens with phase modulation and    -   optionally an opaque mask (M).

In some embodiments, the optical arrangement of step (b) is such that:

-   -   the reference beam (RB) simulates the beam of the build-in image        source to be used for illuminating said holographic mirror so as        to cause the display of the virtual image to be visualized by        the wearer when wearing the frame, and    -   the illumination beam (IB) is configured so as to define        -   the distance of visualization (D) of said displayed virtual            image by the wearer when wearing the frame and/or        -   the direction of visualization of said displayed virtual            image by the wearer when wearing the frame and/or        -   the number of areas of the holographic mirror for the            visualization of said displayed virtual image by the wearer            when wearing the frame.

In some embodiments, the optical arrangement of step (b) is such thatthe illumination beam (IB) is configured so as to differentially recorda plurality of areas (A1, A2, NV, FV) on the film (F) of unrecordedholographic medium, optionally wherein each area (A1, A2; NV, FV)corresponds to equal or distinct values of distance of visualization (D;D_nv, D_fv) of said displayed virtual image by the wearer and/orcorresponds to equal or distinct directions of visualization of saiddisplayed virtual image by the wearer.

In some embodiments, the optical arrangement of step (b) is such thatthe illumination beam (IB) is configured in accordance with an ergorama,wherein said ergorama defines the distance of visualization (D) and/ordirection of visualization of said displayed virtual image by the weareras a function of the gaze directions when wearing the frame. In someembodiments, the wearer is ametropic and said method is a method forproviding a progressive addition lens (respectively a multifocal lenssuch as such as a bifocal ophthalmic lens, respectively a single-visionlens), wherein the ophthalmic lens of step (a) is a progressive additionlens (respectively a multifocal lens such as a bifocal ophthalmic lens,respectively a single-vision lens), and wherein the holographicrecording of step (b) is performed so that the holographic mirror (HM)comprises at least an area for near vision (NV) and an area for farvision (FV) corresponding to distinct values of distance ofvisualization (D_nv, D_fv) of displayed virtual image by the wearer.

In some embodiments, the wearer is ametropic and said method is a methodfor providing a single-vision lens, wherein the ophthalmic lens of step(a) is a semi-finished lens blank, wherein the optical arrangement ofstep (b) includes the implementation of an auxiliary single-vision lens(AL) whose optical power takes into account the optical power requiredto correct the wearer's ametropia and the optical power of thesemi-finished lens blank, and wherein the auxiliary single-vision lens(AL) is for spatially configuring the reference beam (RB) or theillumination beam (IB).

Lenses of the Invention

The present invention provides an ophthalmic lens configured forcorrecting at least partially the wearer's vision for the visualizationof a displayed virtual image, wherein said ophthalmic lens comprises aholographic mirror (HM) or a film (F) of unrecorded holographic medium,optionally wherein said ophthalmic lens is selected from single-visionlenses, multifocal lenses such as bifocal lenses and progressiveaddition lenses, and semi-finished lens blanks.

In some embodiments, said ophthalmic lens is intended to be fitted ontoa frame and worn by said wearer, wherein said ophthalmic lens comprisesa holographic mirror (HM) and wherein said frame comprises a build-inimage source configured for illuminating said holographic mirror so asto cause, upon reflection onto said holographic mirror, thevisualization of a virtual image by the wearer.

In some embodiments, said holographic mirror (HM) is made from amaterial (respectively, said holographic medium is) selected fromdichromated gelatins and photopolymers, and wherein said holographicmirror (HM) (respectively, said film (F) of unrecorded holographicmedium) is provided on the front surface of the ophthalmic lens, on therear surface of the ophthalmic lens, or between the front surface andthe rear surface of the ophthalmic lens.

In some embodiments, the wearer is ametropic and the ophthalmic lens isa progressive addition lens (respectively a multifocal lens such as abifocal ophthalmic lens, respectively a single-vision lens), and theholographic mirror (HM) comprises at least an area for near vision (NV)and an area for far vision (FV) corresponding to distinct values ofdistance of visualization (D_nv, D_fv) of displayed virtual image by thewearer, wherein said ophthalmic lens is configured for correcting atleast partially the wearer's ametropia for the visualization of saiddisplayed virtual image.

In some embodiments, the holographic mirror (HM) comprises at least anarea for near vision (NV) and an area for far vision (FV), and

wherein the holographic mirror (HM) is configured so that it has anaddition with a negative value, wherein the addition of the holographicmirror is defined as the difference:P_NV−P_FVwherein P_NV is the optical power for near vision and P_FV is theoptical power for far vision.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows views of pairs of eyeglasses of the invention.

FIG. 2 shows lenses of the invention.

FIG. 3 shows principles for recording a holographic mirror (left) andutilization of the mirror by restitution of its optical function invirtual image visualization (right).

FIG. 4 shows an optical arrangement for recording a holographic mirror.

FIG. 5 shows views of pairs of eyeglasses of the invention.

FIG. 6 shows the definition of the reflection plane of a holographicmirror.

FIG. 7 shows views of pairs of eyeglasses of the invention.

FIG. 8 shows principles for recording a holographic mirror andutilization of the mirror by restitution of its optical function invirtual image visualization.

FIG. 9 shows lenses of the invention.

FIG. 10 shows optical arrangements for recording a holographic mirror inaccordance with the invention.

FIG. 11 shows embodiments pertaining to a progressive addition lens ofthe invention (11 a) and an illustration of an ergorama (11 b).

FIG. 12 shows embodiments of lenses of the invention.

FIG. 13 shows optical arrangements for recording a holographic mirror ona semi-finished lens in accordance with the invention.

FIG. 14 shows embodiments of the invention including an electrochromiccell.

FIG. 15 shows optical arrangements for recording a holographic mirror ona lens comprising an electrochromic cell in accordance with theinvention.

FIG. 16 shows an optical arrangement for recording a holographic mirrorwith an extended field on a lens in accordance with the invention.

FIG. 17 shows an optical arrangement for recording a holographic mirrorin accordance with the invention.

FIG. 18 shows optical arrangement for recording a holographic mirror ona lens in accordance with the invention.

FIG. 19 shows an example optical arrangement for recording a holographicmirror on a lens in accordance with the invention.

FIG. 20 shows the variation of fringe contrast as a function of theratio of intensity between the illumination beam and the reference beam.

FIGS. 21-22-23 show lenses of the invention.

FIGS. 24-25 show supply systems of the invention.

Figures are not necessarily drawn to scale and generally are forillustrating purposes on a schematic basis. Sometimes, elements are notshown so as to simplify representation.

Definitions

The following definitions are provided to describe the presentinvention.

“Computer-generated images” are known in the art. According to thepresent invention, computer-generated images comprise anycomputer-generated images, such as 2D- or 3D-diffraction images, 2D- or3D-computer-generated holographic images, any amplitude images etc.Computer-generated images may be used as virtual images.

“Holographic images” are known in the art. Such holographic images canbe displayed by reading (illuminating) holograms. Computer-generatedholograms are also referred to as synthetic or digital holograms.Computer-generated holograms are generally obtained by selecting a 2D or3D image, and digitally computing a hologram thereof. The holographicimage can be displayed by optical reconstruction, namely by illuminating(reading) the hologram with a suitable light beam (reference beam of thehologram). Holographic images can be 2D or 3D.

“Holographic mirror” are known in the art. Such mirrors can be obtainedfrom specific materials such as dichromated gelatins or photopolymers.Photopolymers can be in any physical state (liquid, solid, paste, etc.)and include those solid and those liquid under standard conditions. Themirror function is holographically recorded in the specific material.

Photopolymer formulations contain generally one or more monomers oroligomers presenting at least an ethylenically unsaturated photopolymerizable part and at least a system of photo-initiation ofpolymerization with at least one component that is sensitive to theillumination wavelength. They can contain a combination of aphoto-initiator and a photo-sensitizer that allow the increase of therange of the spectral sensitivity for visible light.

These photopolymer formulations can contain various additives such as,in a not exhaustive list, polymers, solvents, plasticizers, transferagents, surfactants, anti-oxidizing agents, thermal stabilizers,anti-foaming agents, thickeners, levelling agents, catalysts and so on.

Examples of photopolymers include commercial photopolymers, such asOmniDex (E.I. du Pont de Nemours (EP 0377182 A2)), Bayfol HX (Bayer),Darol (Polygrama) or SM-TR Photopolymer (Polygrama).

Depending on their composition, in particular on the presence or not ofsolvents and on their viscosity, different types of processing can beenvisaged. The thickness of the photopolymer layer may be from 1 to 100μm and preferentially from 4 to 50 μm. The formulations containingsolvents can be processed in different ways, for example by spincoating, dip coating spray or bar coating of a plane substrate of glass(mineral or organic), or by spin coating, dip coating or spray coatingon a curved substrate of glass (mineral or organic) in order to obtainthe desired thickness. After coating, a step of evaporation of thesolvent(s) is generally necessary to obtain the layer of photopolymerready to be recorded (FIG. 2(a)).

When the formulations do not contain solvents, they can be used in thesame way if their viscosity is not too high. In this case theevaporation step is not necessary. Nevertheless a preferred methodconsists in the direct encapsulation of the photopolymers between twoglass plates (mineral or organic), with a plane or curved shapes (FIG.2(a)).

Two methods can be used in this case. In the first one, the quantity ofliquid required for a thickness from 5 to 50 μm, depending on thephotopolymer, is deposited on the glass plate. The liquid containsspacers made of glass or polymer, of diameter from 5 to 50 μm adapted tothe final desired thickness. The second glass plate is placed on theliquid drop. It allows the spreading and the confinement of thephotopolymer. After exposition and polymerization the photopolymer issolid (or at least gellified) and it attaches the two glass platestogether. A peripheral sealing is then performed to protect the edge ofthe photopolymer from contacts with liquids or atmosphere that maydamage it along the time.

In the second method, a cell is assembled with two plates of glass(plane or curved) and sealed all along the periphery except at a holethat allows the filling of the cell with the liquid photopolymer. Thefilling can be performed by putting the cell under low pressure orvacuum and plunging it in the photopolymer. The hole is then sealed withorganic glue, for example a glue that polymerizes under UV or thermaltreatment.

Another method comprises:

-   -   the deposition of the photopolymer on a flexible substrate, like        a polymer film, polyester for example,    -   the removal of eventual solvents by evaporation or heating,    -   the transfer of the film coated by the photopolymer onto a        substrate (mineral or organic) with plane or curved shape using        well-known transfer processes and adapting them to used        materials (film and photopolymer) (for example ESSILOR patent        applications WO2007144308 A1, WO2010010275 A2). The photopolymer        can be, in this case, at the surface of the transferred film or        in contact with the substrate.

After deposition of the photopolymer and before its exposure, one needsto let it rest during typically 15 minutes to 2 hours. The stress linkedto the process of deposition disappears during this time. After therecording of the holographic mirror, a post-exposition under UV isperformed to polymerize the residual monomers.

The photopolymer layers can be coloured with photo-sensitizers thatabsorb a part of the visible light. These photo-sensitizers arepreferentially chosen to lose completely their colour after expositionto the visible light. A post-exposition under UV or white light reducesthe residual absorption.

A thermal treatment can be realised depending on the used materials toincrease the refractive index modulation of the hologram and itsdiffraction efficiency.

“Head-mounted display devices” (HMD) are known in the art. Such devicesare to be worn on or about the head of a wearer, includinghelmet-mounted displays, optical head-mounted displays, head-worndisplays and the like. They include optical means for displaying animage for visualization by the wearer. The HMD may provide for thesuperimposed visualization of a computer generated image and of a‘real-life’ vision field. The HMD may be monocular (single eye) orbinocular (both eyes). The HMD of the invention can take various forms,including eyeglasses, masks such as skiing or diving masks, goggles,etc. The HMD may comprise one or more lenses. Said lenses can beselected from prescription lenses. According to the invention, the HMDcomprises a spatial light modulator (SLM). In preferred embodiments, theHMD is a pair of eyeglasses provided with lenses.

“Spatial light modulators” (SLM) are known in the art. Said SLM can be aphase SLM, a phase-only SLM, an amplitude-only SLM, or a phase andamplitude SLM. Where present, the amplitude modulation is preferablyindependent from the phase modulation, and allows for a reduction in theimage speckle, so as to improve image quality in terms of grayscale. ASLM may be:

-   -   a reflective SLM (the light beam that causes the display is        reflected on the SLM). Examples thereof include SLMs made of        LCoS material (Liquid Crystal on Silicon). Possible commercial        sources include Holoeye, Boulder Nonlinear Systems, Syndiant,        Cambridge technologies; or    -   a transmissive SLM (the light beam that causes the display is        transmitted through the SLM). Examples of possible commercial        sources include Boulder Nonlinear Systems and Holoeye

“Image sources” IS are known in the art. According to the invention, animage source IS is any light source that can emit a light beam suitable(arranged, configured) for displaying the image for visualization by thewearer. Visualization occurs after the illumination beam stemming fromthe image source is reflected onto the holographic mirror. Regardingdisplay of holographic images, the light beam comprises the referencebeam for the hologram. The image can be displayed from image data (forexample computer-generated image data.

According to the invention, the IS may be any image source configuredfor the display of virtual images (computer-generated images). It may bea screen (for example OLED, LCD, LCOS, etc.), a phase and/or amplitudeSLM (Spatial Light Modulator) taken in combination with its light source(for example laser, diode laser, etc.), a projector such as apicoprojector (MEMS or DLP, that may use LEDs, diodes lasers, etc.), orany other source. The IS may also include any other image source(computer-generated image source), and/or control electronics and/orpower supply etc.

For monochromatic use, it is preferred that the light beam emitted forimage display comprises green light (wavelengths of about 500-560 nm).Green light is advantageous in that a lower energy (for example <1 mW)is required since the human retina is more sensitive to wavelengths inthis range. Examples of monochromatic light sources with emission atabout 520-550 nm include green OLED displays, class 2 lasers, lasers at532 nm, laser diodes at 520 nm (for example from Osram or Nichia), LEDemitting at around 550 nm, etc. Preferably, the power of themonochromatic source is <10 mW. Other suitable monochromatic lightsources include red: 615-645 nm; green: 520-550 nm; blue: 435-465 nm.

“Frame data” refers to a set of one or more data relating to thestructure of the frame, and may comprise design parameters such as therelative location of one element of the frame. Examples include datasuch as pantoscopic angle, curve, shape and dimensions of the frame,etc. Frame data FD may include at least one image source data ISD. Thisincludes the location of the image source, the relative location(distance and/or spatial orientation) of a image source with referenceto one or both lenses in the frame, the relative location (distance andor spatial orientation) of a image source with reference to one or bothholographic mirrors in the frame. For example, when the image source isimaged trough a lens between the holographic mirror and the imagesource, the relative location is the virtual distance of the imagesource. This also includes data pertaining to the features of the imagesource itself, such as the wavelength/s of emission, the power, theaperture, etc.

“Lens data” (LD) refers to a set of one or more data characterizing anophthalmic lens. Said data comprise data defining one or moregeometrical (surface) characteristics and/or one or more opticalcharacteristics of the lens, such as the optical index of the lensmaterial. Lens data LD may correspond to the back surface of a lensand/or to the front surface of a lens, or their relative positions. Saidlens data LD may further include data pertaining to the general geometryof the lens, for example average radius of curvature, convexity data,etc. Said lens data LD may also comprise data on surface coatings of thelens being present on the lens and characteristics thereof; datapertaining to a holographic mirror being present on the lens andcharacteristics thereof; or data pertaining to any amplitude modulationmaterials such as electrochromic materials being present in the lens andcharacteristics thereof.

“Wearer ophthalmic data” or “ophthalmic data” OD are known in the art.Wearer ophthalmic data include wearer prescription data PD, wearer eyesensitivity data SD and wearer ophthalmic biometry data BD, andgenerally data pertaining to any wearer vision defect, including forexample data pertaining to chromatic aberrations, lack of eye lens(aphakia), etc.

“Prescription data” PD are known in the art. Prescription data refers toone or more data obtained for the wearer and indicating for each eye aprescribed far vision mean refractive power P_(FV), and/or a prescribedastigmatism value CYL_(FV) and/or a prescribed astigmatism axis AXE_(FV)and/or a prescribed addition A suitable for correcting the ametropiaand/or presbyopia of each eye. The mean refractive power P_(FV) isobtained by summing the half value of the prescribed astigmatism valueCYL_(FV) to the prescribed sphere value SPH_(FV): P_(FV)=SPH_(FV)CYL_(FV)/2. Then, the mean refractive power for each eye for proximate(near) vision is obtained by summing the prescribed addition A to thefar vision mean refractive power P_(FV) prescribed for the same eye:P_(NV)=P_(FV)+A. In the case of a prescription for progressive lenses,prescription data comprise wearer data indicating for each eye valuesfor SPH_(FV), CYL_(FV) and A. In preferred embodiments, wearerprescription data PD are selected from astigmatism module, astigmatismaxis, power, prism and addition, and more generally any data indicatingthe correction of any given vision defect. Such defect may result from apartial retinal detachment, retina or iris or cornea malformation,

“Wearer eye sensitivity data” SD are known in the art. Wearer eyesensitivity data include data for spectral sensitivity (to one or morewavelengths or spectral bands); general sensitivity such as brightnesssensitivity, for example for outdoors brightness sensitivity. Such dataare of importance to optimize contrast for visualization of an image bythe wearer.

“Wearer ophthalmic biometry data” or “biometry data” BD are known in theart. Biometry data include data pertaining to the morphology of thewearer, and typically include one or more of monocular pupillarydistance, inter-pupillary distance, axial length of the eye, position ofthe centre of rotation of the eye, punctum remotum, punctum proximum,etc.

DETAILED DESCRIPTION OF THE INVENTION

Virtual Image Visualization in Accordance with the Invention

Holography techniques are known in the art. They generally involve firsta step of recording on a suitable medium such as a holographic support,and then a step of reconstructing the holographic image. Recordinggenerally involves dual illumination of the medium with a reference beamand an illumination beam. Reconstructing the holographic image can beperformed by illuminating the recorded medium with the reference beam.

In broad terms, the present invention implements a recording step, butdoes not involve the reconstructing step as described above.

According to the invention, a recording step is used so as to record(impart) an optical function in a film F of holographic material. Theresulting (recorded film) is a mirror that is used to reflect a beamfrom the image source, so as to cause visualization of a virtual imageby the wearer.

This is illustrated by FIG. 3 and FIG. 8 wherein the holographic mediumis a holographic mirror: the left part shows medium recording and theright part shows visualization of the virtual image (from the imagesource) by the wearer. An image source IS provides a beam thatilluminates the holographic mirror. The beam from the IS is reflected onto the mirror towards an eye of a subject. In FIG. 3, the virtual imageto be visualized is situated at infinite (or very large) distance of thewearer. FIG. 8 illustrates visualization of the virtual image in asituation of pupil conjugation. The virtual image is formed on the eyepupil.

The recording of a mirror can be performed in accordance with an opticalarrangement. An exemplary optical arrangement is shown on FIG. 4. Onthis figure, the recording implements a laser. A polarization beamsplitter PBS allows to ‘divide’ the beam. References signs PMF arepolarization-maintaining fibers. The split of the beam provides for twobeams: a reference beam RB illuminating one side of a holographicrecording medium, and an illumination beam IB illuminating the otherside of the holographic medium. This allows the recording of aholographic mirror HM. Once the optical arrangement is set (e.g.geometry, sizes of the beams, etc.), features of the holographic mirrorcan be modified by varying one or more parameters, including the powerratio between the two beams (impacts the fringe contrast and thediffraction efficiency), the exposure time (impacts the diffraction anddiffusion efficiency—see FIG. 20 that shows the variation of fringecontrast as a function of the ratio of intensity between theillumination beam and the reference beam), and the possible use ofrotatable supports for the ends of the fibers (impacts the polarizationof the beams when exiting the PMF fibers). Examples of parameters for anoptical arrangement are shown on FIG. 19 (F: film of holographicmaterial to be recorded, PBS: polarization beam splitter, PMF:polarization-maintaining fiber, RL: recording lens, IB: illuminationbeam, RB: reference beam).

In general terms, the present invention relates to systems, methods andlenses.

The present invention provides an ophthalmic lens intended to be fittedonto a frame and worn by a wearer, wherein said ophthalmic lenscomprises a holographic mirror and wherein said frame comprises abuild-in image source configured for illuminating said holographicmirror so as to cause, upon reflection onto said holographic mirror, thevisualization of a virtual image by the wearer. The lens may beconfigured to correct the wearer's virtual vision.

This means that virtual vision (visualization, by the wearer, of avirtual image), results from the illumination, by the build-in imagesource of the frame, of the holographic mirror present in the lens. Asmentioned herein, said ophthalmic lens may be configured for either anametropic wearer or an emmetropic wearer. According to the invention, insome aspects, said ophthalmic lens is advantageously configured forcorrecting the wearer's ametropia for both natural vision and thevisualization of said displayed virtual images. In some embodiments, thewearer's ametropia for virtual vision may be fully corrected or at leastpartially corrected. In some aspects: for an emmetropic wearer naturalvision may not be corrected and virtual vision may be corrected, forexample as a function of gaze directions and/or as a function ofdistance of visualization.

Exemplary frames with a lens of the invention are shown on FIGS. 1, 5and 7.

The image source IS is situated on the frame, for example at the templelevel, on an eyeglasses side stem. The image source IS emits a beamtowards the lens. The beam is then reflected by the holographic mirrorin the lens towards the eye of the wearer for visualization of thevirtual image. In some embodiments, the light beam emitted from the ISmay first be deflected by a holographic deflector H deft. The use of adeflector or of any other deflecting component (prism, microprism,holographic component, grid, collimating and/or deflecting lens,combinations thereof, etc.) allows to spatially configure (e.g. orient,compact, etc.) the beam from the IS.

The holographic mirror is thus-off-axis. Further, the mirror is curved,in that its optical function is ‘curved’: it converts a spherical waveinto either a different spherical wave (for example for virtual image innear-vision), or into a planar wave (virtual image situated at theinfinite). This makes it complex to provide a holographic mirror for usein an ophthalmic lens that would correct the wearer's ametropia for bothnatural vision and visualization of a virtual image. For example, theconfiguration of the frame may take into account the orientation andthus the solid angle of light emission from the IS. For example, FIG. 5shows different orientations of the image source and illustrate thesolid angle of emission of the IS (dashed lines). The configuration ofthe frame also defines an angle between the reflection plane of theholographic mirror and the frame. This is illustrated at FIG. 6 (ReflPl: reflection plane, HM: holographic mirror, IS: image source, E: eyeof the wearer). The lateral position of the IS (x, y on FIG. 7) withrespect to the holographic mirror defines the centering of the imagewith respect to the gaze of the wearer. The longitudinal position of theIS (z on FIG. 7) is of importance. The location of the IS is ofimportance, because it directly affects the intensity of the wavereflected by the mirror, so that an incorrect positioning generates avirtual image with optical aberrations (S, C, Axis, higher-orderaberrations). Such parameters should be taken into account for theconfiguration of the frame.

Further, it is desirable that the wearer can visualize virtual images atdifferent distances, for example virtual images in near vision andvirtual images in far vision.

Also, the lens comprising a holographic mirror may have differentstructures, wherein the holographic mirror HM may be situated on the eyeside (rear) surface of the lens, on the front surface of the lens(opposite from the eye) or between the front and the rear surfaces (inthe ‘bulk’) of the lens.

Thus, advantageously according to the invention, there are providedsystems, lenses and methods that take into account the wearer'sametropia, notably prescription data.

According to the invention, the features of the holographic mirror maybe defined ‘globally’ in terms of a virtual optical function. Thisfunction takes into account the light path taken by the beam,independently of the exact mechanical structure of the lens. This takesinto account possible refractions in the lens, and in any event, thereflection on the HM. This approach may thus be applied for all possiblelens structures, for example: light path from the IS with a singlereflection on the HM (HM located on rear side of lens); or light pathfrom the IS with a first refraction on the rear side of the lens, thenreflection on the HM, then again refraction on the rear side of thelens, and then to the wearer eye (HM situated on the front side of thelens). The virtual optical function may advantageously be defined inaccordance with an ergorama. Said ergorama may define the distance ofvisualization (D) and/or direction of visualization of said displayedvirtual image by the wearer as a function of the gaze directions whenwearing the frame.

Systems of the Invention

The present invention provides an ophthalmic lens supply system.

This system is for providing an ophthalmic lens intended to be fittedonto a frame and worn by a wearer, wherein said ophthalmic lenscomprises a holographic mirror and wherein said frame comprises abuild-in image source configured for illuminating said holographicmirror, so as to cause, upon reflection onto said holographic mirror,the visualization of a virtual image by the wearer.

The ophthalmic lens provided by the system is configured for correctingthe wearer's virtual vision,

According to the invention, in some aspects, said ophthalmic lens isadvantageously configured for correcting the wearer's ametropia for bothnatural vision and the visualization of said displayed virtual images.In some aspects: for an emmetropic wearer natural vision may not becorrected and virtual vision may be corrected, for example as a functionof gaze directions and/or as a function of distance of visualization.

The supply system comprises:

-   -   first processing means PM1 configured for placing an order of an        ophthalmic lens, wherein said first processing means PM1 are        located at a lens ordering side LOS and comprise:        -   inputting means IM1 configured for the input of wearer            prescription data WPD,        -   optionally, inputting means IM2 configured for the input of            frame data FD, wherein said frame data FD comprise at least            one image source data LSD;    -   second processing means PM2 configured for providing lens data        LD based upon wearer prescription data WPD, wherein said second        processing means PM2 are located at a lens determination side        LDS and comprise outputting means OM configured for outputting        said lens data LD, and    -   first transmission means TM1 configured for transmitting said        wearer prescription data WPD and optionally for transmitting        said frame data FD, from said first processing means PM1 to said        second processing means PM2.

Frame data FD may include one or more of image source data ISD (forexample one or more of spatial configuration, location, distance fromlens or from mirror, emission angle, etc.; also see above definition).Such data may be made from selection in a catalogue or from customizedinformation as requested by a wearer.

In some embodiments, the supply system may further comprise thirdprocessing means PM3 configured for the input of one or more furtherdata, such as one or more values of distance of visualization of thevirtual image, data pertaining to the visualization direction, thenumber of areas for the HM (for example the presence of at least onearea for virtual visualization in near vision and at least one area forvirtual visualization in far vision; also see below)

The lens ordering side LOS is typically at the premises of an eye careprofessional or optician where lenses are ordered for wearers(customers).

Each of the above imputing means IM may be any inputting meansconfigured for the input of the relevant data. Said inputting means arepreferably selected for facilitated interface (e.g. may be used inconnection with displaying means), and may be a keyboard from a computersuch as a PC or laptop, tablet, handset, terminal, remote, etc. The lensdetermination side LDS is equipped with processing means that mayadvantageously be suitable for performing any one of the lensdetermination methods as known in the art.

In some embodiments, said supply system may optionally further comprise:

-   -   manufacturing means MM configured for manufacturing an        ophthalmic lens based upon lens data LD and frame data FD,        wherein said manufacturing means are located at a lens        manufacturing side LMS, and    -   second transmission means TM2 configured for transmitting said        lens data LD from said second processing means PM2 to said        manufacturing means MM,        wherein said manufacturing means MM comprise means configured        for recording a holographic mirror.

In some embodiments, the frame data FD may be transmitted from the LOSto the LDS and then to LMS. In some embodiments, the frame data FD maybe transmitted directly from the LOS to the LMS.

The lens manufacturing side LMS is generally located in an optical lab,namely a place equipped with manufacturing means for manufacturinglenses following lens orders, based upon lens data previously obtainedor generated.

Lens manufacturing means MM are known in the art, and the skilled personis familiar with suitable manufacturing means. Said manufacturing meansmay include one or more of surfacing including digital surfacing,polishing, edging means, etc. The lens manufacturing side LMS maycomprise a combination of manufacturing means, including severaldifferent surfacing means, and/or several polishing means, etc. Meansconfigured for recording a holographic mirror are known in the art, andare further described herein in some aspects of the invention.

The lens manufacturing side may further comprise inputting meanssuitable for receiving the information from said second processing meansand further transmit the information to the relevant manufacturingmeans.

In an alternative embodiment, the supply system may further comprise:

-   -   fourth processing means PM4 wherein said fourth processing means        PM4 are located at a frame ordering side LFS and comprise        inputting means IM4 configured for the input of frame data FD,        wherein said frame data FD comprise at least one image source        data LSD; and        -   fourth transmission means TM4 configured for transmitting            said frame data FD from said fourth processing means PM4 to            LOS, LDS or LMS.

The person skilled in the art is familiar with suitable transmittingmeans useful in the field of lens supply systems. Suitable means includeelectronic communications, such as by internet connections, for examplevia one or more servers, e-mail communication, and the like.

In one aspect of the invention, the first and/or the second and/or thethird and/or the fourth processing means PM1, PM2, PM3, PM4 may be acomputer entity and may comprise a memory MEM. The computer entities maybe connected to each other through one or more servers. Said servers maycomprise storing means in the form of a memory.

Memories are known in the art and the skilled person is familiar withmemories that that suitable for implementation within a lens supplysystem. The memory may be suitable for storing data, such as: inputdata, output data, intermediate data (such as intermediate computationresults). The memory may be useful as a working memory and/or to storesequence of instructions. The memory may be provided in one or morestoring elements/means, and may be part of a server.

Exemplary ophthalmic lens supply systems of the invention arerepresented schematically at FIGS. 24-25.

Methods of the Invention

The present invention relates to a method for providing an ophthalmiclens intended to be fitted onto a frame and worn by a wearer. Saidophthalmic lens comprises a holographic mirror HM and wherein said framecomprises a build-in image source configured for illuminating saidholographic mirror so as to cause, upon reflection onto said holographicmirror, the visualization of a virtual image by the wearer, wherein saidophthalmic lens is configured for correcting the wearer's virtualvision.

According to the invention, in some aspects, the wearer is ametropic andsaid ophthalmic lens is advantageously configured for correcting thewearer's ametropia for both natural vision and the visualization of saiddisplayed virtual images. In some aspects: for an emmetropic wearernatural vision may not be corrected and virtual vision may be corrected,for example as a function of gaze directions and/or as a function ofdistance of visualization.

These methods can advantageously be implemented in a lens manufacturingmethod.

As disclosed herein, in some embodiments, the wearer's ametropia forvirtual vision may be fully corrected or at least partially corrected.

In accordance with the invention, said method comprises a step (a) ofproviding an ophthalmic lens having a front surface and a rear surface,wherein said ophthalmic lens comprises a film F of unrecordedholographic medium. Holographic media are known in the art. Such mediainclude dichromated gelatines and photopolymers as described herein. Insome embodiments, the holographic medium may be photopolymer provided inliquid form. In such case, the film may be formed between two glasslayers (walls), so as to be ‘encapsulated’. Said glass layer may beprovided in addition to the lens of step (a), or the lens of step (a)may play the role of one of the glass layers, or (see below) the wall ofan amplitude modulation cell may play the role of one glass layer. In apreferred embodiment, the film may be ‘encapsulated’ between the lens ofstep (a) and a glass layer/wall, wherein the film may be provided eitherat the front surface or at the rear surface of the lens (see FIG. 12,structures shown in the right hand column). Using one glass wall insteadof two makes the lens less heavy, which is advantageous. Typical glasswall thickness can be 300-2000 μm. Examples of glass layer materialinclude organic or mineral glass. In some embodiments, the film may havea thickness of 20-30 μm (for example for dichromated gelatines) or of5-50 μm (for example for liquid photopolymers). In some embodiments, inthe ophthalmic lens of step (a), the unrecorded holographic medium isselected from dichromated gelatines and photopolymers, and the film F ofunrecorded holographic medium is provided on the front surface of theophthalmic lens, on the rear surface of the ophthalmic lens, or betweenthe front surface and the rear surface of the ophthalmic lens. The filmF may preferably be provided so as to cover the entirety of the surfaceof the lens (or equivalent if inserted in the bulk of the lens).

Reference is made to the description provided in the definitions aboveunder ‘holographic mirror’).

In some embodiments, the ophthalmic lens of step (a) is configured forcorrecting the wearer's ametropia for natural vision and is selectedfrom single-vision lenses, multifocal lenses such as bifocal lenses, andprogressive addition lenses.

In some embodiments, said ophthalmic lens may optionally furthercomprise an amplitude modulation cell. Said amplitude modulation cellmay for example be selected from electrochromic cells, polarizing cellsand photochromic cells. Such cells are known in the art. Where the lenscomprises a photochromic cell, it may be advantageously be such that thephotochromic material does not darken during step (b) and/or does notdegrade upon illumination from the LS.

Possible structures for the ophthalmic lens are depicted on FIGS. 2, 9,12 and 14; L (Rx): lens, such as corrective lens, for exampleprescription lens, F: film of unrecorded holographic material, HM:holographic mirror; G: glass wall or layer; EC: electrochromic materialor cell (can more generally be any amplitude modulation material orcell). As can be seen on these figures, various structures areencompassed within the present invention, and the HM may be situated atthe rear surface or the front surface of the lens, optionally with oneor more glass walls G and/or an EC layer or cell. All possiblecombinations are herein envisioned.

Further, said holographic mirror (HM) (respectively, said film (F) ofunrecorded holographic medium) is provided on the front surface of theophthalmic lens, on the rear surface of the ophthalmic lens, or betweenthe front surface and the rear surface of the ophthalmic lens.

The method of the invention comprises a step (b) of performingholographic recording of said holographic medium by generatinginterference between a reference beam RB and an illumination beam IB soas to provide an ophthalmic lens comprising a holographic mirror HM,wherein the holographic recording is performed in an optical arrangementthat takes into account at least the configuration of the frame.

Advantageously according to step (b), the configuration of the RB mimics(simulates) the configuration of the IS on the frame, with respect tothe HM in the lens fitted into the frame. In particular, the spatialconfiguration of the RB reflects the spatial configuration implementedfor recording the mirror once the lens is fitted into the frame(orientation, distance, breadth (shape and size of zone projected on thelens), etc.). The physical location of the image source IS build-in onthe frame may thus further define a secondary (re-imaged) correspondingimage source (for example, image source S′1 on FIG. 23 that is imaged ata different position versus the physical position of S1, using the lensL1, that may be adjustable in position or have adjustable focal). Thus,the configuration of the IB may reflect emission from the physical imagesource IS, or from a secondary (re-imaged) image source.

Advantageously according to the invention, the optical arrangement ofstep (b) allows to provide with a holographic mirror that leads to thedesired optical function, namely the holographic mirror obtained by step(b) is ‘automatically’ configured for providing the suitable opticalfunction for at least partially correcting the wearer's ametropia forvirtual vision through the lens.

See FIG. 10.

As shown on the right part of FIG. 10, for the first case where the filmF is on the front side of the lens L, a light beam from the image sourceIS pass through the lens L and is reflected on the holographic mirrorHM. The reflected wavefront WF is the same than the wavefront of theillumination beam IB, meaning that the virtual image seems to “come”from infinity, ie as the natural image. The lens corrects thus thenatural vision and the vision of the virtual image at the same time.When the film F is on the rear side on the lens L, the wavefront of theillumination beam after crossing the lens L is divergent on the film F.A beam of the image source IS is thus reflected with the same wavefrontthan the real image seen through the lens L, and the virtual image seemsto be originate from the same place than this real image. To achievethat, the lens may have a value of power identical or close to theprescription data PD of the wearer.

As illustrated in FIG. 13, the lens can so be the finished lens havingpower identical or close to PD, or a combination of a semi finished lensand a complementary lens AL, this combination having powers identical orclose to PD.

In some embodiments, the method of the invention may optionally comprisea step (c) of cutting the lens obtained from step (b).

In some embodiments, the optical recording of step (b) may further takeinto account the distance of visualization (D) of said displayed virtualimage by the wearer when wearing the frame and/or the direction ofvisualization of said displayed virtual image by the wearer when wearingthe frame and/or the number of areas of the holographic mirror for thevisualization of said displayed virtual image by the wearer when wearingthe frame.

Said recording may thus be performed in accordance with an ergorama asdefined herein. The ergorama defines the distance of visualization d (indioptres δ) as a function of the gaze direction defined in an (α,β)angular system of coordinates: each gaze direction (α,β) corresponds toa given distance of visualization. Illustration of an exemplary ergoramais provided at FIG. 11b . For example, in near vision (α=35° and) β=5°),one may have a distance of visualization of 30-50 cm.

In some embodiments, the optical arrangement of step (b) is configuredsuch that the illumination beam IB is spatially configured with:

-   -   one or more recording lenses RL, RL1, RL2 selected from unifocal        lenses, multifocal lenses such as bifocal lenses, and        progressive addition lenses, or a lens matrix LM, or an active        lens with phase modulation and    -   optionally an opaque mask M.

Active lenses with phase modulation include deformable optical systems,such as fluidic systems, piezoelectric mirrors, transmission SLMs, andmore generally systems with variable (tunable) power.

Advantageously according to the invention, one or more recording lens RLand/or one or more mask M may be used to spatially configure the IB thatilluminates the HM. This provides for the differential and/or sequentialrecording of defined areas in the HM. See for example FIGS. 16-18.

In some embodiments, the optical arrangement of step (b) is configuredsuch that:

-   -   the reference beam RB simulates the beam of the build-in image        source to be used for illuminating said holographic mirror so as        to cause the display of the virtual image to be visualized by        the wearer when wearing the frame, and    -   the illumination beam IB is configured so as to define        -   the distance of visualization D of said displayed virtual            image by the wearer when wearing the frame and/or        -   the direction of visualization of said displayed virtual            image by the wearer when wearing the frame and/or        -   the number of areas of the holographic mirror for the            visualization of said displayed virtual image by the wearer            when wearing the frame.

The distance of visualization D may be infinite (very large) or finite.

In some embodiments, the optical arrangement of step (b) is such thatthe illumination beam IB is configured so as to differentially record aplurality of areas A1, A2, NV, FV on the film F of unrecordedholographic medium. In such case, each area A1, A2; NV, FV maycorrespond to equal or distinct values of distance of visualization D;D_nv, D_fv of said displayed virtual image by the wearer and/or maycorrespond to equal or distinct directions of visualization of saiddisplayed virtual image by the wearer. The variation from one to anotherarea (in terms of acuity correction) may be continuous (progressive) ornot. See for example FIG. 16.

In some embodiments, as explained above, the optical arrangement of step(b) is such that the illumination beam IB is configured in accordancewith an ergorama, wherein said ergorama defines the distance ofvisualization D and/or direction of visualization of said displayedvirtual image by the wearer as a function of the gaze directions whenwearing the frame. The definition of said ergorama may include at leastgaze directions in the vertical direction and/or gaze directions in thehorizontal direction (β=constant and/or α=constant). See for exampleFIG. 11b . The ergorama may also be defined differently according to thegaze directions of interest, corresponding to the areas of interest onthe lens.

In some embodiments, said method is a method for providing a progressiveaddition lens (respectively a multifocal lens such as a bifocalophthalmic lens, respectively a single-vision lens), wherein theophthalmic lens of step (a) is a progressive addition lens (respectivelya multifocal lens such as a bifocal ophthalmic lens, respectively asingle-vision lens), and wherein the holographic recording of step (b)is performed so that the holographic mirror HM comprises at least anarea for near vision NV and an area for far vision FV corresponding todistinct values of distance of visualization D_nv, D_fv of displayedvirtual image by the wearer. See for example FIG. 17.

Advantageously, the method of the invention provides lenses (e.g.unifocal, multifocal such as bifocal, progressive addition)) thatprovide for dual virtual vision, with the HM mirror specificallyconfigured to comprise at least an area for virtual near vision and atleast an area for virtual far vision.

In some embodiments, the method provides a lens that comprises aamplitude modulation cell as described herein, such as an electrochromiccell. See for example illustrative optical arrangements in FIG. 15.

In some embodiments, said method may be a method for providing asingle-vision lens (respectively a multifocal lens such as a bifocallens, respectively a progressive addition lens), wherein the ophthalmiclens of step (a) is a semi-finished lens blank SF, wherein the opticalarrangement of step (b) includes the implementation of an auxiliarysingle-vision lens AL (respectively an auxiliary multifocal lens such asa bifocal lens, respectively an auxiliary progressive addition lens)whose optical power takes into account the optical power required tocorrect the wearer's ametropia and the optical power of thesemi-finished lens blank, and wherein the auxiliary single-vision lensAL (respectively an auxiliary multifocal lens such as a bifocal lens,respectively an auxiliary progressive addition lens) is for spatiallyconfiguring the reference beam RB or the illumination beam IB. See forexample FIG. 13.

As an alternative to implementing an auxiliary lens (AL), it is possibleto directly change the wavefront coming from IB or RB using an activelens with a modulation phase, for example a varying power lens usingadaptive optics technics.

In some embodiments, the IB is such that it covers an extended field onthe lens. See for example FIG. 16.

The methods of the invention are illustrated on the following figures:

FIG. 10 shows optical arrangements for recording a holographic mirror inaccordance with the invention, and the utilization of the mirror in theframe/restitution of the optical function of the holographic mirror for(corrected) virtual image visualization. At the left are illustrationsof optical arrangements. By recording (center of figure), the wave frontWF is deformed between the lens of step (a) and the film F. Thereconstruction of the virtual image is shown on the right withillumination from the IS. The F may be at the front surface (top) orrear surface (bottom) of the lens of step (a).

FIG. 11a shows embodiments pertaining to a progressive addition lens fora presbiopic wearer having no more accommodation capability. If thewearer cannot accommodate or very little accommodate, this will decreasetolerance values for suitable focus distances. The simplest case is thatof a non-myopic but presbyopic wearer. S/he has a prescription for aplano lens and a positive addition (Vc). In this case, it is necessaryfor the image reflected by the mirror to be visualized at infinitedistance regardless of the lens area (gaze direction). In the opticalarrangements of FIG. 10, the area with the addition does not allow for areflected image to be directly situated at infinite distance. It istherefore advantageous to “neutralize” this addition for the recordingof the HM. One ‘simple’ possibility is to have two identical lenses (Rxfor prescription and its counterpart). Recording may be performed withthese two lenses. The Rx lens may be arranged directly on or below theplane of the film F/holographic mirror HM (or in another embodiment, theholographic mirror/film HM/F may be directly attached to theprescription lenslens that will be lens provided to the wearer), and thesecond lens may be at a distance equal to the sum of the focal additions(FIG. 11a left). This is achieved with the assembly of FIG. 10 (bottomright). Another possibility is to use a plano/divergent progressivelens, with a plano part corresponding to the plano part of theprescription lens, and a divergent part such that its focal length (f)and the distance (e) to the lens meets the equation f=fc−e, where fc isthe focal length of the addition (FIG. 11a right). To change theprescription lens, it is possible to simply adjust the distance betweenthe lens and the gradual plano/divergent lens, or to keep this distanceconstant, but change the progressive lens.

FIG. 13 shows optical arrangements for recording a holographic mirror ona semi-finished lens in accordance with the invention. Depending on therelative location of the film F of holographic medium (either frontsurface or rear surface of the semi-finished blank SF, the auxiliarylens AL is positioned respectively at the rear surface or front surfaceof the semi-finished lens. In this embodiment, one requires the value ofprescription for which that SF will be used. This is thus particularlyadvantageous for SV lenses. For recording, one may take into accountboth the power of the SF and the prescription value Rx intended to beachieved. If the SF has a power V_(SF) and the desired power value isS_(RX), one may add a lens (auxiliary lens. AL) with a power V such thatV=V_(RX)−V_(SF) (provided that the distance between the SF and AL issmall compared to the focal of these glasses). This applies to botharrangements (see FIG. 13).

FIG. 15 shows optical arrangements for recording a holographic mirror ona lens comprising an electrochromic cell in accordance with theinvention. The presence of an electrochromic cell EC does not affect therecording, and it may be present during recording. Advantageously, thefilm F may be formed (‘sandwiched’) between the lens of step (a) and theEC cell.

FIG. 16 shows an optical arrangement for recording a holographic mirrorwith an extended field on a lens in accordance with the invention. Theextended field may allow to cover the entirety of the lens surface,whereby the entirety of the lens surface is illuminated by the IB beam.The IB beam may be configured so as to define several areas A1, A2 onthe film/mirror F/HM. This is advantageous in that it provides forvirtual vision in several gaze directions, corresponding to therespective areas of the film/mirror/lens.

FIG. 17 shows optical arrangement for recording a holographic mirror ona lens in accordance with the invention (lens of step (a) not shown).This illustrates the implementation of one or more recording lenses RL,possibly in combination with one or more masks, to spatially configurethe illumination beam IB and/or the reference beam RB. Thisadvantageously allows to record areas of the film F on a differentialbasis, and in particular to record differentially and/or sequentially atleast two distinct areas, such as at least one area for near vision NVand one area for far vision FV. This method is useful for any type oflens at step (a). In particular, the lens of step (a) may be a plano. Insuch case, it provides a lens that is suitable for an emmetropic wearer,wherein the lens provides for a virtual vision with suitable focusdistance/s as a function of the gaze direction.

FIG. 18 shows optical arrangement for recording a holographic mirror ona lens in accordance with the invention. The lens matrix LM also allowsto differentially record areas of the film, for example with a divergentmatrix used to generate the illumination beam for the near vision area(left). It is also possible to use a progressive addition lens PAL as arecording lens RL. This advantageously provides for a progressive focusdistance to be implemented. This also advantageously provides for a lensto be worn by an emmetropic wearer, wherein the lens of step (a) can bea plano. For example, it is possible to use a divergent PAL to recordthe near vision NV area of the film F.

Lenses of the Invention

The present invention provides an ophthalmic lens for correcting atleast partially the wearer's vision for the visualization of a displayedvirtual image, wherein said ophthalmic lens comprises a holographicmirror HM or a film F of unrecorded holographic medium.

In some embodiments, the lens may be configured for correcting awearer's ametropia in natural vision and/or virtual vision. In someembodiments, the wearer may be emmetropic, and the lens is such that itprovides for corrected virtual vision. This may for example be desirablefor a wearer who, despite being emmetropic, lacks sufficient reservesfor accommodation. Thus, in some aspects: for an emmetropic wearernatural vision may not be corrected and virtual vision may be corrected,for example as a function of gaze directions and/or as a function ofdistance of visualization.

In some embodiments, said ophthalmic lens may be selected fromsingle-vision lenses, multifocal lenses such as bifocal lenses,progressive addition lenses and semi-finished lens blanks.

In some embodiments, said ophthalmic lens is intended to be fitted ontoa frame and worn by said wearer.

In some embodiments, said ophthalmic lens comprises a holographic mirrorHM and said frame comprises a build-in image source configured forilluminating said holographic mirror, so as to cause, upon reflectiononto said holographic mirror, the visualization of a virtual image bythe wearer, wherein said ophthalmic lens is configured for correcting atleast partially the wearer's ametropia for the visualization of saiddisplayed virtual image. The fact that the wearer's ametropia may not befully corrected is illustrated below (example 2). The corresponding‘tolerance’ values of the examples may apply to all lenses of theinvention.

In some embodiments, said holographic mirror HM is made from a material(respectively, said holographic medium is) selected from dichromatedgelatines and photopolymers. Said material and medium are as disclosedherein.

In some embodiments, said holographic mirror HM (respectively, said filmF of unrecorded holographic medium) is provided on the front surface ofthe ophthalmic lens, on the rear surface of the ophthalmic lens, orbetween the front surface and the rear surface of the ophthalmic lens.Possible structures for the ophthalmic lens are depicted on FIGS. 2, 9,12 and 14. All possible combinations thereof are herein envisioned. Inthis respect, the stacking structure may be any stacking structure asdescribed herein.

In some embodiments, said ophthalmic lens optionally further comprisesan amplitude modulation cell, for example selected from electrochromiccells, polarizing cells and photochromic cells, as described herein.

In some embodiments, the ophthalmic lens is a progressive addition lens(respectively a multifocal lens such as a bifocal ophthalmic lens,respectively a single-vision lens), and the holographic mirror HMcomprises at least an area for near vision NV and an area for far visionFV corresponding to distinct values of distance of visualization D_nv,D_fv of displayed virtual image by the wearer. D_nv and D_fv may haveequal or different values. The variation in distance from NV to FV maybe continuous or not. Correspondingly, the power variation for virtualvision may vary in a continuous fashion or not. This may be illustratedin particular by FIG. 17.

In some embodiments, the holographic mirror HM may comprise at least anarea for near vision NV and an area for far vision FV, and theholographic mirror (HM) may be configured so that it has an additionwith a negative value, wherein the addition of the holographic mirror isdefined as the difference:P_NV−P_FVwherein P_NV is the optical power for near vision and P_FV is theoptical power for far vision. The optical power of the holographicmirror is defined as the curvature, expressed in dioptres of thewavefront after reflexion onto the holographic mirror and after exitingthe lens, from a point in the image source. A concave curvature refersto a positive value of power, while a convex curvature refers to anegative value of power.

In some embodiments, the absolute value of (P_NV−P_FV) decreases as theprescribed value of addition increases.

For the lenses of the invention, reference is also made to FIGS. 2, 9,11, 12, 14 and 21-22.

Pairs of Eyeglasses and HMDs of the Invention

The present invention also provides eyeglasses (spectacles) as well asmore generally head mounted devices. Said devices and eyeglassescomprise at least one lens according to the invention, or at least onelens obtained in accordance with the invention, as described herein.

FIGS. 1, 5 and 7 show exemplary eyeglasses according to the invention.

All embodiments of lenses, methods, eyeglasses, HMDs and systems hereindescribed (including figures) may be partially or fully combined witheach other.

The invention is illustrated by the following non-limiting examples.

EXAMPLES Example 1: Method and Lens of the Invention

FIG. 19 shows an example optical arrangement for recording a holographicmirror on a lens in accordance with the invention. In this example thelaser emits at 532 nm.

PMF is a polarization-maintaining fiber (460-HP Nufern): panda fiber,core diameter 2.5 μm, ON 0.13, mode diameter: 3.5 μm @ 515 nm.

The lens of step (a) is not shown.

The lens is as follows: power −3δ, front surface radius 87 mm, shapeeyeglasses lens 40×50 mm or round diameter 70 mm. Stacking of layers isas per FIG. 12, top left.

The film F is as follows: diameter 70 mm, radius of curvature 87 mm,glass layer thickness 850 μm, photopolymer F thickness 5 to 50 μm (e.g.40 μm) thanks to spacers, total stacking thickness ˜1.65 mm, exposuretime: 30 s to 10 min depending upon nature of photopolymer.

Depositing the film F for a lens of 70 mm diameter:

-   -   depositing a 50 μL drop onto a glass layer (spacers: 5-50 μm,        glass layer: thickness 500 μm; radius of curvature 87 mm, round        diameter 70 mm; anti-reflection treatment or coating, especially        532 nm),    -   positioning second glass layer; tightening,    -   leave at rest for 20 min onto the illumination support member.        Illumination for 30 s to 6 min, as a function of the beam        intensity (e.g. see FIG. 20), nature and thickness of        photopolymer.    -   Bleaching by exposition to visible light for 15 min (e.g.        halogen lamp, 50 to 75 W).    -   Sealing with glue if necessary.        During illumination:    -   protect from physical disturbance (air movements, mechanical        vibrations, dust, etc.)    -   stabilized temperature (avoid air convection)    -   black room (dark room: for example inactinic lighting for        recording green light)    -   coating (anti-reflection) onto glass (avoiding parasite        reflections).        Characterization:    -   Spectral (wavelength for reflection and mirror efficiency)    -   Qualitative optical properties (observe an OLED screen)    -   Quantitative optical properties (wave front analysis).        It is possible to combine with an EC cell.

Example 2: Lenses of the Invention

The present example relates to a finished or semi-finished lens.Situation 3B below may apply for a finished lens or a combination of asemi-finished lens with an auxiliary lens (AL) with a progressivesurface.

The below features generally illustrate that, according to theinvention, ametropia may be either partially or fully corrected forvirtual vision.

1. Spherical Power in a Far Vision Zone

If the lens has a spherical power Sv in a far vision area, then therecording of the holographic mirror may be such that the wave frontafter reflection on the holographic mirror and exiting the lens(refraction) has a spherical power Sh close to Sv, in the far visionregion.

In practice, this power value Sh power may

-   -   be less than the power Sv, within a magnitude not exceeding 2δ        (this therefore may impose a value of wearer accommodation of        2δ, because the virtual image will be visualized at a distance        of 50 cm=1/(2δ)).    -   not exceed Sv by 1δ (eye field depth of field)

-   Thus: Sv≈Sh, preferably Sv−2δ≤Sh≤Sv+1δ.

This applies preferably for a configuration wherein the image sourcepoint is at a fixed location (FIGS. 21 and 22) but also in the casewhere the source point is imaged with an adjustable position lens L1, inthis case one can envision to partially correct the sphericalprescription by adjusting the focus.

See FIG. 21. T: temporal side, N: nasal side, SV: single vision lens.

On this figure, the spherical powers Sv and Sh are equal on the entiretyof the surface of the lens: S=−1δ.

2. Cylindrical Power

If the lens has a cylinder power, characterized by a power Cv and acylinder axis Av, then the recording of the holographic mirror is suchthat wave front after reflection on the holographic mirror and exitingthe lens (refraction), has a cylinder power Ch and cylinder axis Ah ofvalues identical or close to those of the lens.

It can be considered that the difference in cylinder power between Cvand Ch should be equal or below 0.25 D, preferentially of ≤1δ.

-   Thus: Ch≈Cv and Av≈Ah,-   Preferably abs(Cv−Ch)≤0.25δ or 0.5δ or 1δ-   Preferably abs (Av−Ah)≤10° for cylinders ≤0.5δ    -   abs (Av−Ah)≤4° for cylinders ≥0.5δ.        3. Features of the Holographic Mirror as a Function of Lens        Areas (Gaze Directions)

See FIG. 22. FV: far vision, NV near vision.

Several situations may be identified.

3A. Unifocal Lens

Preferably, the wave surface after reflection on the holographic mirrorand exiting the lens (refraction) is such that it has a negative powerchange (negative addition) between the upper part (area) of the lens andthe lower part (area) of the lens.

Indeed, the implementation of a negative addition at the lower part ofthe lens allows to bring the virtual image at a finite distance forvisualization, and thus brings the virtual image and the real field ofview into in the same vision plane (generally, the lower part of thelens is used for gaze directions towards an object located at closedistance). This allows to simultaneously visualize with acuity thevirtual image and the real image.

For example, the SV lens wearer observes, through the lower part of thelens, an object situated at a distance of 33 cm. Therefore accommodationis of 3.33δ. In order to see the virtual image with acuity, this imageshould be positioned at −33 cm, so that the wave surface reflected bythe mirror has a power −3.33δ.

-   Thus: 0≥Addh=Sh_lower−Sh_upper-   Preferably: 0≥Addh=Sh_lower−Sh_upper≥−3,5δ or −4δ    The variation in addition (Addh) may be continuous or not.

3B. Progressive Addition Lens

In this case, the lens has a progressive design, characterized byprescription values for far vision (Sv, Cv, Av) in the FV area of thelens, and an addition value which is reached in the near vision area(Addv).

The recording of the holographic mirror is such that the wave surfaceafter reflection on the holographic mirror and exiting the lens(refraction) has a power variation Addh, wherein Addh is such that

ADDH this power variation is:

-   -   its sign is opposite to that of Addv: Addh<0    -   its amplitude increases as the value of addition Addv decreases:        abs (Addh) varies in the opposite direction to abs (Addv),    -   the power variation of the wave surface reflected by the        hologram following the position of the lens power variation: the        value of Addh is reached on the lens in the NV area wherein the        value of Addv is also reached, and follows the same trend.        For example:    -   An emmetropic presbyopic wearer with a value of addition of 1.5δ        has an accommodation reserve of at least 1.8δ in order to focus        at a distance of 33 cm (3.3δ). Therefore the virtual image may        be situated at a distance of −55 cm at the nearest, which        corresponds to a power change of −1.8δ to the wave surface        reflected by the holographic mirror.    -   An emmetropic presbyopic wearer with a value of addition of 3.5δ        has no reserve of accommodation. Therefore the virtual image        should be positioned at infinite distance for virtual acuity,        therefore the variation in power of the wave surface reflected        by the hologram is zero or close to zero.

3C. Orientation of the Wave Surface Generated by the Holographic Mirror

See FIG. 22. The image source S′1 is imaged from source S1 trough a lensL1. The holographic mirror is recorded such that the wave front does nothave the same inclination.

The wave surface reflected by the mirror is essentially horizontal inthe region of far vision of the lens. It has an upward inclination inthe lower area of the glass, so that the light rays are directed towardthe eye.

This may be reflected in the fact that the focal point of the wavesurface reflected by the mirror is located in lower position withrespect to the optical axis of the lens.

The invention claimed is:
 1. An Ophthalmic lens supply system forproviding an ophthalmic lens configured to be fitted onto a frame andworn by a wearer, said ophthalmic lens comprising a holographic mirrorand said frame comprising a build-in image source configured forilluminating said holographic mirror so as to cause, upon reflectiononto said holographic mirror, the visualization of a virtual image bythe wearer, said ophthalmic lens being configured for correcting thewearer's virtual vision, said supply system comprising: first processingmeans configured for placing an order of an ophthalmic lens, whereinsaid first processing means are located at a lens ordering side andcomprise: inputting means configured to input wearer prescription data;inputting means configured to input frame data, wherein said frame datacomprise at least one image source data; second processing meansconfigured for providing lens data based upon wearer prescription data,wherein said second processing means are located at a lens determinationside and comprise outputting means configured for outputting said lensdata, and first transmission means configured for transmitting saidwearer prescription data and for transmitting said frame data, from saidfirst processing means to said second processing means; manufacturingmeans configured for manufacturing an ophthalmic lens based upon lensdata and frame data, wherein said manufacturing means are located at alens manufacturing side; and second transmission means configured fortransmitting said lens data from said second processing means to saidmanufacturing means, wherein said manufacturing means comprise meansconfigured for recording the holographic mirror by performingholographic recording of a film of unrecorded holographic medium bygenerating interference between a reference beam and an illuminationbeam to provide the ophthalmic lens comprising the holographic mirror,wherein the holographic recording is performed in an optical arrangementthat takes into account at least the configuration of the frame, suchthat the illumination beam is configured to differentially record aplurality of areas on the film of unrecorded holographic medium, andwherein each area corresponds to equal or distinct values of distance ofvisualization of said displayed virtual image by the wearer, orcorresponds to equal or distinct directions of visualization of saiddisplayed virtual image by the wearer.
 2. A method for providing anophthalmic lens configured to be fitted onto a frame and worn by awearer, wherein said ophthalmic lens comprises a holographic mirror andwherein said frame comprises a build-in image source configured forilluminating said holographic mirror to cause, upon reflection onto saidholographic mirror, visualization of a virtual image by the wearer, saidophthalmic lens being configured for correcting the wearer's virtualvision, said method comprising: providing an ophthalmic lens having afront surface and a rear surface, wherein said ophthalmic lens comprisesa film of unrecorded holographic medium; and performing holographicrecording of said holographic medium by generating interference betweena reference beam and an illumination beam to provide an ophthalmic lenscomprising a holographic mirror, wherein the holographic recording isperformed in an optical arrangement that takes into account at least theconfiguration of the frame, wherein the optical arrangement is suchthat: (i) the illumination beam is configured to differentially record aplurality of areas on the film of unrecorded holographic medium, whereineach area corresponds to equal or distinct values of distance ofvisualization of said virtual image by the wearer, or corresponds toequal or distinct directions of visualization of said virtual image bythe wearer, and (ii) the reference beam simulates the beam of thebuild-in image source to be used for illuminating said holographicmirror, to cause display of the virtual image to be visualized by thewearer when wearing the frame.
 3. The method according to claim 2,wherein the holographic recording further takes into account a distanceof visualization of said displayed virtual image by the wearer whenwearing the frame, or a direction of visualization of said displayedvirtual image by the wearer when wearing the frame, or the number ofareas of the holographic mirror for the visualization of said displayedvirtual image by the wearer when wearing the frame.
 4. The methodaccording to claim 2, wherein the wearer is ametropic, and wherein theophthalmic lens is configured for correcting the wearer's ametropia fornatural vision and is selected from single-vision lenses, multifocallenses such as bifocal lenses and progressive addition lenses.
 5. Themethod according to claim 2, wherein, in the ophthalmic lens: theunrecorded holographic medium is selected from dichromated gelatins andphotopolymers, and the film of unrecorded holographic medium is providedon the front surface of the ophthalmic lens, on the rear surface of theophthalmic lens, or between the front surface and the rear surface ofthe ophthalmic lens.
 6. The method according to claim 2, wherein theoptical arrangement is such that: the illumination beam is configured todefine a distance of visualization of said displayed virtual image bythe wearer when wearing the frame, or a direction of visualization ofsaid displayed virtual image by the wearer when wearing the frame, orthe number of areas of the holographic mirror for the visualization ofsaid displayed virtual image by the wearer when wearing the frame. 7.The method according to claim 2, wherein the wearer is ametropic,wherein said method is a method for providing a progressive additionlens, respectively a multifocal lens, respectively a single-vision lens,wherein the ophthalmic lens is a progressive addition lens, respectivelya multifocal lens, respectively a single-vision lens, and wherein theholographic recording is performed so that the holographic mirrorcomprises at least an area for near vision and an area for far visioncorresponding to distinct values of distance of visualization ofdisplayed virtual image by the wearer.
 8. The method according to claim2, wherein the wearer is ametropic, wherein said method is a method forproviding a single-vision lens, respectively a multifocal lens,respectively a progressive addition lens, wherein the ophthalmic lens isa semi-finished lens blank, wherein the optical arrangement includesimplementation of an auxiliary single-vision lens, respectively anauxiliary multifocal lens, respectively an auxiliary progressiveaddition lens, whose optical power takes into account the optical powerrequired to correct the wearer's ametropia and the optical power of thesemi-finished lens blank, and wherein the auxiliary single-vision lens,respectively the auxiliary multifocal lens, respectively the auxiliaryprogressive addition lens, is for spatially configuring the referencebeam or the illumination beam.
 9. The method according to claim 2,wherein the providing the ophthalmic lens further comprises an amplitudemodulation cell selected from electrochromic cells, polarizing cells andphotochromic cells, and wherein the method further comprises cutting thelens obtained from the performing holographic recording.